JPS5960954A - Electron beam exposure device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an electron beam exposure bag fc, and in particular to a magnetic field generated from an anode formed as a magnet with both poles, to eliminate electron aberration caused by an electrostatic lens system. This paper relates to an electron beam exposure system with a triple-electrode electron gun for better offset.

(2) Background of the Technology When drawing an IC pattern at high speed using an electron beam exposure apparatus equipped with a triode electron gun, if an aberration occurs in the electron beam, the brightness decreases and drawing becomes impossible. Aberrations of electron beams are caused by the electric field of an electrostatic lens system, and attempts have been made to cancel out these aberrations by applying a magnetic field.

(3) Prior Art and Problems FIG. 1 is a side view schematically showing a conventional triode electron gun using only an electrostatic lens system. In FIG. 1, 1 represents a cathode, 2 represents a grid, and 3 represents an anode. A high voltage of about -20 KVO is applied to the cathode 1 and grid 2, and the anode 3 is grounded. The electron flow emitted from the cathode 1 toward the anode 3 is controlled to be focused at a desired position on the IC pattern by the electric field formed by the grid 2, but in reality, aberrations occur as shown in the figure. . Attempts have been made to cancel this aberration by applying a magnetic field.

FIG. 2 is a side view schematically showing a three-pole electron gun using a conventional magnetic field application method. In FIG. 2, the grid 2' and the anode 3' are made of magnetic material, and by passing a current through the coil 4 wound between the grid 2' and the anode 3', the grid 2' is Anode 3' to N pole
is magnetized to the south pole.

The cathode 1 and the green throat 2' have −
A high voltage of 20 KVO is applied and the anode 1' is grounded. Aberrations of the electron beam due to the electric field formed by the grid 2' (and C due to the magnetic field between the grid 2' and the anode 3' are somewhat canceled out).

However, the conventional type shown in FIG. 2 has the following problems.

The first problem is that when the grid 2' becomes hot and approaches the Curie point of iron (approximately 700° C.), the strength of the magnetic field becomes unstable and the grid 2' becomes useless as a magnetic pole. The grid 2' is placed close to the cathode 1, and since the temperature of the cathode 1 reaches approximately 2800°C, the grid 2' is heated by the cathode 1 and
The temperature will reach 00°C or higher.

The problem with 8'c2 is that the magnetic field is between grid 2' and anode 3.
Since the magnetic field does not reach between the grid 2' and the cathode 10, the effect of canceling out the aberration caused by the electric field is not sufficient.

That is, since the green throat 2' is a magnetic material, it functions as a magnetic shield.

The third problem is that it is difficult to manufacture.

That is, the cathode 1, grid 2', and anode 3' perform all electrostatic system control, and the grid 2' and anode 3' control the magnetic field system, but in this case, the static TLC system is controlled. and the control of the magnetic field system must be performed along the same axis of the electron beam. In this batch,
The central axis of the hole I, which is provided in the center of the grid 2' and through which the electron beam passes, must coincide with the center axis of the hole H, which is provided in the center of the anode 3', and which the electron beam passes through. Must be tl.

However, it is extremely difficult to form the holes H1 in the grid 2' so that their central axes coincide with the anode 3'.

The fourth problem is that there is a gap between the grid 2' and anode 3'.
Since a high crawling pressure of 0 KV is applied, a gap S must be provided between the grid 2' and the anode 3' on the side opposite to the magnetic pole to prevent discharge, and this gap S prevents magnetic flux leakage. This means that the strength of the magnetic field between magnetic poles N-8 is weak.

Due to the above-mentioned problems, the conventional type shown in FIG. 2 cannot provide a sufficiently focused electron beam for printing the C pattern at high speed.

(4) Object of the Invention In view of the problems with the conventional type described above, the object of the present invention is to form a grid r using a non-magnetic material and provide a triple-pole electron gun based on the concept of having both magnetic poles on the anode. In the electron beam exposure system H, by stably and accurately applying a strong magnetic field, the aberration of the electron beam due to the electrostatic field is sufficiently canceled out by the magnetic field, thereby making it possible to draw IC patterns at high speed with the electron beam. It depends on making it possible.

(5) 41g of the Invention The gist of the present invention to achieve the above object is to provide a cathode that emits electrons, a grid that controls the path of the electrons emitted from the cathode, and a grid that controls the fc electrons controlled by the cathode. The grid is made of a non-magnetic material, and the anode has a three-pole electron gun having an anode that accelerates the
A second annular magnetic body provided with a full gap between a first annular magnetic body centered on the first annular magnetic body and the second annular magnetic body,
The electron beam is formed as a magnet 7 with an IJ body, and the aberration caused by controlling the path of electrons by the grid is canceled out by the magnetic field generated by the magnet of the anode. It's in the exposure equipment.

(6) Embodiments of the invention Examples of the invention will be described below with reference to FIGS. 3 to 6.

FIG. 3 is a side view showing the triode electron gun of the electron beam exposure apparatus according to the first embodiment of the present invention. In Figure 3,
] and 28 designate a cathode and grid similar to that of FIG. It should be noted that the grid 2a is made of non-magnetic material. 3a is an anode provided according to the invention.

4 and 5 are a top plan view and a partially cutaway perspective view of the anode 3a shown in FIG. 3, respectively. Third
As shown in Figures 5 to 5, the anode 3a has a third annular magnetic body 6a whose center line is the information 5, which is the traveling direction of the electron beam, and a coil storage area on the outside of this annular magnetic body 6a. A second annular magnetic body 8a is provided with a gap 7a, and a coil 9a is wound in the gap 7a. In consideration of the deflection of the electron beam for drawing, the inner diameter d of the anode 3a increases as the distance from the cathode 1 increases. In the part facing the grid 2&, the first annular magnetic body 6a of the anode 3a has an S pole, and the second
The coil within the gap 7a is wound so that the annular magnetic body 8a forms a north pole. At the bottom of the anode 3a, a first annular magnetic body 6a, ! : Second annular magnetic body 8a
are integrated.

The structure of the electron beam exposure apparatus shown in FIGS. 3 to 5 eliminates all the problems in the conventional example. In other words, since the grid 2a does not contribute to the formation of the magnetic field,
Even at high temperatures, the strength of the magnetic field does not become unstable.

Since the grid 2a is a non-magnetic material, it has no magnetic shielding effect, so the lines of force at the anode 3a reach the space between the cathode 1 and the grid 2a, so the electrons due to the electrostatic field The effect of canceling beam aberrations is improved.

Furthermore, since the magnetic field system is controlled only by the anode 3a, alignment of the grid and the anode becomes easy, and therefore, the construction of the first and second structures becomes easier. Furthermore, since the first annular magnetic body 6a and the second annular magnetic body 8a are both grounded and at the same potential, there is no need to provide a gap for preventing discharge as in the conventional example, so there is little magnetic field leakage. A strong magnetic field can be obtained.

FIG. 6 is a side view showing a triode electron gun of an electron beam exposure apparatus according to a second embodiment of the present invention. In Figure 6,
A cylindrical anode 3b is used in place of the volcano-shaped anode 3a shown in FIG. 3, and the other configurations are the same as in the dcl embodiment. The anode 3b in this example is
Cylindrical first annular magnetic body 6b,! : A second annular magnetic body 8b is provided, and a coil 9b is provided in the gap 7b between these.
is wound. The second annular n31R8b is a hollow disc 10 at the portion facing the grid 2b, and a gap is provided between the annular gaps 6b of the hollow discs ]0 and 4]. 3, the first annular magnetic body 6b and the second annular magnetic body 8b are integrated at the lower part;
It is clear that the embodiment shown in FIG. 6 also provides the same effects as the first embodiment.

(7) As described in detail, according to the present invention, the grid is formed of a non-magnetic material and the anode has both magnetic poles.
Since a strong magnetic field can be stably and accurately applied to the electron beam, the convergence Ze caused by the electrostatic field of the electron beam can be sufficiently canceled out, and as a result, the ■c pattern can be drawn at high speed with the electron beam. It becomes possible.

[Brief explanation of drawings]

Figure 1 is a side view schematically showing a conventional triode electron gun using only an electrostatic lens system. Figure 2 is a side view schematically showing a triole electron gun using a conventional magnetic field application method. The figure shows the electron beam exposure system fff according to the first embodiment of the present invention.
Side view without showing pole 1d lineage, Figure 4''? 5 and 5 are respectively a top plan view and a partially cutaway perspective view of the anode 3a shown in FIG. FIG. 1...Cathode, 2a, 2b...Grid. 3a, 3b...anode. 6a, 6b...first annular magnetic body. 7a, 7b...Gap for coil storage. 8a, 8b... second annular magnetic body. 9a, 9b...Coil. Figure 1 ■ Figure 2 Figure 4

Claims (1)

[Claims] 1. A three-pole electron gun including a cathode that emits electrons, a grid that controls the path of the electrons emitted from the cathode, and an anode that accelerates the electrons controlled by the cathode, and the grid is nonmagnetic. The anode is made of a material whose axis is in the direction in which electrons travel.
The system is formed as a magnet including a first annular magnetic body centered on the axis and a second annular magnetic body provided with a gap between the first annular magnetic body and the second annular magnetic body. An electron beam exposure apparatus characterized in that an aberration caused by controlling the path of electrons by the grid is offset by a magnetic field generated by the magnet of the anode.